The Analgesic Efficacy and Safety of Venlafaxine for Prevention of Postherpetic Neuralgia in Patients With Acute Herpes Zoster

Postherpetic neuralgia (PHN) is the most common complication of herpes zoster (HZ) and represents a major clinical challenge due to its chronicity and impact on quality of life. Current treatments for acute HZ pain have limited efficacy in preventing PHN, highlighting the need for effective preventive strategies targeting early pathophysiological mechanisms. Venlafaxine as a plausible and clinically relevant candidate for early intervention to prevent the transition from acute HZ pain to PHN.

Inclusion Criteria: * 1\. Ages more than 18 years; * 2\. Patients with onset of HZ rash less than 30 days; * 3\. Experiencing moderate to severe HZ pain with an average pain score of at least 4 on a Numeric Rating Scale (NRS, 0 = no pain, 10 = worst possible pain); * 4\. Aspartate aminotransferase and alanine aminotransferase levels less than twice the upper limit of normal; * 5\. Estimated glomerular filtration rate of 30 mL/min per 1.73 m2 or higher; * 6\. Willing to sign the informed consent form and possessing sufficient cognitive and language abilities to comply with all the study requirements. Exclusion Criteria: * 1\. HZ with head, neck, ocular, mucous membrane, cranial nerve, or central nervous system involvement or generalized HZ; * 2.Known hypersensitivity to venlafaxine; * 3\. Previous antiviral treatment that did not comply with guideline recommendations; * 4\. History of herpes zoster vaccination before enrollment; * 5.History of major depressive disorder requiring antidepressant therapy; * 6.History of systemic immune diseases, organ transplantation, or cancers; * 7.Pregnancy or lactation; * 8.Presence of acute or chronic pain disorders other than HZ.